Need advice on a seized up L4701 HST in Northeast Texas

rawdeal77

New member

Equipment
L4701
Dec 12, 2023
2
0
1
Naples, TX
I have a 2019 L4701 HST with 300hrs on it. I was running it with a brush hog when temp started to sail like the thermostat was stuck. I immediately shut it down let it cool off, restarted and let it idle to make sure temp stabilized, and then started heading back to the house. On the way, while the temp showed to be normal, the motor seized up and wouldn't restart. Tractor was less than 20 hours from coming from the dealership after being "serviced to hours."

Mechanic said there's compression on cylinders 1 and 2, but 3 is bad. I'm told it could just be a head gasket, but thinks it is more likely something worse that will require the engine to be rebuilt. Quoted $7k for the head gasket job, and $12k for a rebuild or same price to just put in a new/reman engine.

Does this sound reasonable?

Any referrals where I can source a good reman v2403 for a L4701 in the U.S.?

Or even better, any referrals for a trustworthy/reasonable Kubota mechanics in North East Texas?
 

GeoHorn

Well-known member
Lifetime Member

Equipment
M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
5,827
3,099
113
Texas
The mechanic who has quoted the cylinder compressions….. is the local Kubota guy? …or is it some other…??
Is it a “real diesel” mech…?…or just someone you know that has a set of tools?

I’m not simply trying to “jump” you… I’m just as incredulous as yourself that it costs $7K for a head gskt. This is a $1K - $1.5K job at most.

BTW, an overtemped engine commonly results in a blown head gskt.

If it also resulted in a cracked head… THEN I’d believe a $7K repair.
 

Vigo

Well-known member

Equipment
B6100, B8200
Jan 9, 2022
595
340
63
San Antonio Texas
That's an unusual circumstance to be sure.

ASE Master Tech here, but not a diesel specialist by any means. I do have a light diesel ASE Cert though, and all the basics are universal..

Such as. Seized vs compression test. Seized means the engine won't spin. Compression test REQUIRES the engine to spin. So was the engine ever seized?

It IS possible for engines to seize up when hot and then spin again once they cool off. Generally this is because aluminum pistons grow more than the iron cylinders they ride inside, so at some temperature the piston-to-wall clearance shrinks to nil and the engine seizes up because the pistons become tight in the bore. This is a very unhappy circumstance in some cases because of a couple of things: 1. If you are making a lot of power the engine won't stop, it will grind itself to pieces until you lower the power level enough for it to 'lock up'. A lot of damage is done to cylinders and pistons in this time. The other bad scenario is 2. The engine was under low power, the extra drag from the pistons stopped the engine without too much rubbing damage, BUT the piston rings themselves overheated to the point that they lose their 'tension' or 'springiness' and no longer push out against the bore, causing loss of compression.

So it's not impossible for the engine to have seized right there in the field, but then been able to crank later for a compression test. I'm just looking for a little clarification on the chain of events regarding the engine spinning or not spinning.
 

rawdeal77

New member

Equipment
L4701
Dec 12, 2023
2
0
1
Naples, TX
Thank you Vigo and Geohorn for the quick response. I will reply to both of you here.

Geohorn, This was not a Kubota tech per se, but it is a busy ag/auto repair shop who claims to do a lot of diesel work. He said his "hunch" about needing a new motor or a rebuild was based on the sound of the piston moving in the cylinder.

Vigo, I misdescribed the condition as "seized." To be sure, the engine never seized up. I suddenly sputtered and died while in a high idle state traveling down a roadway. Immediately after it died, when I tried to restart, it would turnover without issue, but it would not crank.
 

GeoHorn

Well-known member
Lifetime Member

Equipment
M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
5,827
3,099
113
Texas
OK…well then…your reply is enlightening as regards the issuer of the “sound-based-hunch”….which is not a logical method of diagnosis.

I suggest you find another shop which has experience in diesel tractors.
 

Jim L.

Active member
Jun 18, 2014
818
93
28
Texas
First, sorry your machine is down.

That this happened when mowing says to me that under heavy load the cooling system could not keep up. Besides the thermostat, the cleanliness of the radiator should be suspect (outside fins).

The problem with #3 says to me that the only way to know what it will take is to open it up. I would not be optimistic that it is the gasket- but opening up means it gets replaced anyway. The price quoted means that this is a job he really does not want to do, but will if the money is in it.

My opinion would be to check around Texarkana and Sulphur Springs to fix the problem. Putting it on a trailer would to me cost less in the long run. Sorry I don't know the right shop in you area.
 

jaxs

Active member

Equipment
B1750HST
Jun 22, 2023
456
226
43
Texas
Sorry this happened to you. Those quotes are ridiculous but many trades are still wallowing in excess as result of all that Monopoly money handed out in 20 & 21. Besides hooking up with the right mechanic you also face the challenge on what to do with torn down tractor while locating an engine if this one is ruined or costs more to to fix than buying a used engine. Do you have space to store tractor after it's torn down if necessary? No mechanic wants a bay tied up while you find parts or engine. Until head is off you can't know what lies ahead.
 

Poohbear

Active member

Equipment
L3301 HST, LA525, LP shredder, BB1566 box blade, QH10, Worksaver pallet fork
Jul 6, 2018
472
133
43
Gilmer,Tx,United States
Can you give a little more precise area than NE Tx. ? Greenville, Sulphur Springs, Terrell ,Mt. Pleasant ? The Mahindra/New Holland dealer in Mt. Pleasant has a really good reputation for getting stuff fixed .
 

Runs With Scissors

Well-known member

Equipment
L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
Jan 25, 2023
1,882
1,998
113
Michigan
First, sorry your machine is down.



The problem with #3 says to me that the only way to know what it will take is to open it up. I would not be optimistic that it is the gasket- but opening up means it gets replaced anyway. The price quoted means that this is a job he really does not want to do, but will if the money is in it.
+1 I agree. (y)


No mechanic wants a bay tied up while you find parts or engine.

Yep...and neither do Service Managers/Owners I'm sure.